Habitat fragmentation compromises the population dynamic of the globally near-threatened Straight-billed Reedhaunter (Limnoctites rectirostris)

Abstract

AbstractUnderstanding the consequences of habitat fragmentation to biological populations is crucial to develop sound conservation polices. The Straight-billed Reedhaunter (Limnoctites rectirostris) is a little known and threatened Passeriform that is highly dependent Erygo wetlands patches. Here, we evaluated the effects of habitat fragmentation on populations of the Straight-billed Reedhaunter, during the construction of a water reservoir in southern Brazil. During eight months, we monitored five Eryngo wetlands patches occupied (n=3) and no occupied (n=2) by Straight-billed Reedhaunter individuals, collecting data on their temporal occupancy patterns and registering new fragmentation events in formally continuous habitat patches. We evaluated the consequences of habitat fragmentation on the probabilities of patch occupancy, colonization and extinction of populations of the Straight-billed Reedhaunter using an information-theoretic approach. Out of the three patches occupied by Straight-billed Reedhaunter, two were not altered by construction activities and their populations were present during the entire study period. After fragmentation events, local extinction in one of the wetland patches was observed, and individuals were sporadically observed in two other initially unoccupied sites. The model in which fragmentation affected only the extinction probability was the most plausible among the set of candidate models. Fragmentation greatly increased the chance of local population extinction within patches. Our results indicate that the conservation of populations of the Straight-billed Reedhaunter is highly dependent on continuous and unaltered wetland patches.